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SERVICE BULLETIN NOTICE: The Type of Change and Recommended Compliance specified reflects Solar’s best judgment regarding the Service Bulletin. All questions should be directed to your Solar Field Service Representative. Solar, Saturn, Centaur, Taurus, Mercury, Mars, Titan, SoLoNOx, and Turbotronic are trademarks of Solar Turbines Incorporated. Cat and Caterpillar are trademarks of Caterpillar Inc. Specifications subject to change without notice. NUMBER: 2.1/107 ISSUED: August 1995 REVISED: PRODUCT: Mars MODEL(S): All Specifics: With pneumatic starters and/or pneumatic auxiliary backup or seal oil pumps. SUBJECT: PULSATIONS IN AIR/GAS DRIVEN STARTER MOTORS OR AUXILIARY/BACKUP LUBE/SEAL OIL PUMPS. Type of Change: Product Improvement Recommended Compliance: Operation and Information Purpose: To announce the availability of modified trims for the Fisher 310 pressure regulating and shutoff valves, and the availability of a new, lined flex hose to the pneumatic starter. GENERAL INFORMATION: Visible oscillations in the start gas supply line (Item 18; Figure 1) and audible "hunting" of pneu- matic motors (starter and/or aux. pump motors) have been reported in some instances. The pipe and hose oscillations can lead to early failures in the start gas supply hose. Two possible sources of the oscillations have been identified: 1. L o w f r e q u e n c y v i b r a t i o n ( - 1 t o 3 H z ) . These frequencies are excited by a "hunting" regulator (Fisher 310) and will cause speed variation of pneumatic motors. These speed variations can be clearly heard near the regu- lators and pneumatic motors. Affected are the 1" valves used as a regulator/shutoff valve for the emergency pre/post lube pump or the auxiliary/backup seal oil pump, and the 2" SERVICE BULLETIN Page 1 of 19 NUMBER: 2.1/107

valve for the pneumatic starter. If the 2" valve for the starter is unstable, the inlet flange of the 2" pipe (Item 18; Figure 1) between the flex hose and pneumatic starter may visi- bly vibrate, alternately stretching and compressing the flex hose (Item 9; Fig.1). Several customers have already addressed this problem by installing additional brackets to the pipe and/or by controlling the flex hose length by replacing some flange studs with long threaded rods parallel to the flex hose (from one flange to the other). The problem is more pronounced at low gas flows (regulator nearly closed), but once excited, the hunting often does not stop until the pneumatic motors are switched off completely. The valve opening area in the regulators is highly nonlinear and has an extremely high gain near the closed position. Starter motors and auxiliary seal oil pumps are required to operate in this region at certain times. 2. H i g h f r e q u e n c y v i b r a t i o n i n t h e s t a r t e r f l e x h o s e . In unlined flex hoses, the pressure drop is very high due to the rough surface inside the hose (convolutions). The gas striking the individual convolutions can set up high frequency vibrations, which destroy the convolutions by fatigue. Small cracks can appear after very few starts. Bent hoses are more critical than straight ones and should be avoided. ACTION REQUIRED: 1. O s c i l l a t i n g F i s h e r r e g u l a t o r s If excessive hunting can be observed in the start or auxiliary oil systems, the Fisher regulators supplying the pneumatic motors should be inspected and modified. 2. S t a r t e r m o t o r p r e s s u r e r e g u l a t o r P C V 9 2 1 - 1 ; F i s h e r 3 1 0 , 2 " . This valve can be stabilized by merely replacing the existing valve trim with an "equal percentage" trim as offered by Fisher (disk retainer, item 12, Figure 2). 3. O n e i n c h F i s h e r 3 1 0 p r e s s u r e r e g u l a t o r s d r i v i n g t h e a u x i l i a r y / b a c k u p l u b e o r s e a l o i l p u m p s . In these applications replacing the valve trim only does not fully correct the problem. In addition the shutoff solenoid valve has to be relocated, and the long 3/8" pressure sensing line from the pneumatic motor has to be enlarged to 1/2". The solenoid valves activating the system (L320-X, L366-X) have to be relocated from the sensing line into the pilot gas supply line (after the filter). Figure 3 shows a typical schematic with the existing and the new, modified plumbing. The modification does not change the control logic to the solenoid valve. The valve still has to be energized to switch off the auxiliary pump, but the pilot gas circuit is now depressurized when the auxiliary pump is shut off. Due to the multitude of different packages (many have no pneumatic auxiliary pumps) and the different style connectors, no specific tubing kit has been developed for this Page 2 of 19 SERVICE BULLETIN NUMBER: 2.1/107

• Disc Retainer, Solar P/N992761C1 Plumbing Modifications • 1/2" tubing and connectors (flare or Swagelok) to increase sensing line size. • 3/8" connectors, brackets and conduit to relocate solenoid valve. 2. S t a r t e r f l e x h o s e : • If the plumbing looks like figure 1 and flex hose P/N 183077-XXX is presently used: • 1 ea. Flex hose P/N 231615 • 2 ea. gasket, 2.0" 300 lbs P/N 965213C1 • If the package looks like Figure 2 or uses one long hose only, add manifold 18 ( Figure 1) and elbow 19 to above parts. Choose either the carbon steel (CS) or the stainless steel (SS) version. 1 ea. Flex hose P/N 231615 1 ea. elbow P/N 231505-100 (CS) or P/N 231505-300 (SS) 1 ea. manifold P/N 231506-100 (CS) or P/N 231506-300 (SS) 3 ea. gasket, 2.0" 300 lbs P/N 965213C1 1 ea. gasket, 2.5" 150 lbs P/N 967976C1 16ea. stud/nut assembly 5/8 11x4 P/N 970902C1 PROCEDURE: Use the following procedure to modify the existing Fisher 310 pressure regulators (1" or 2" valves): 1. Isolate pneumatic system from all gas/air sources. 2. Lock and tag shutoff valves. 3. Bleed line and remove Fisher 310 regulator from system. 4. Disassemble main valve (pages 9 and 10 in Fisher Manual; see attachment) and remove Disc Retainer/Seat (key 12). 5. Replace Disc Retainer with new Fisher "equal percentage" trim and reassemble as per instructions in Fisher manual (pages 10 and 11) with the following exception: Do not tighten cap screw (key 10) more than finger tight at this time. 6. After main valve is reassembled, connect an air source (0-20 PSIG; 0-1.4 bar) to the loading pressure port of the main valve (downstream side of main diaphragm; Figure 4). Increase the air pressure to this port and watch the main valve sleeve (key 3, Fisher manual) for movement. Page 4 of 19 SERVICE BULLETIN NUMBER: 2.1/107

The sleeve should start to move off the Disc Retainer/seat as the loading pressure reaches 10 to 15 PSIG (0.6 to 1.0 bar). Increase the loading pressure to 20 PSIG (1.4 bar) and then reduce to zero. Repeat the cycle several times to allow the sleeve to center the Disc Retainer/Seat. 7. Remove the temporary air line and reconnect the loading tube from the pilot assembly. 8. Use a long extension to tighten the cap screw (key 10) that secures the Disc Retainer/Seat. 9. Reinstall regulator into the system. 10. Modify plumbing arrangement (1" regulator only) as described above (see schematic Figure 3). 11. Install a pressure gage (200 or 300 PSIG scale; 15 or 20 bar) downstream of the regulator or into the regulated pressure sensing line. 12. Remove tags; open isolation valves and pressurize system. Check for leaks. 13. Operate system; check for leaks and note any pressure oscillations in the regulated pressure (activate lube system if you run the starter or the auxiliary/backup seal oil pump). 14. Shut down system; isolate system from air/gas sources and remove pressure gage installed in step 11. 15. Open isolation valves. SERVICE BULLETIN Page 5 of 19 NUMBER: 2.1/107

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